A car exploded in front of a Coptic Christian church as worshippers emerged from a New Year's Mass in the Egyptian city of Alexandria early Saturday, killing at least seven people, officials said.

After the blast, enraged Christians emerging from the church clashed with police and stormed a nearby mosque, prompting fights and volleys of stone throwing with Muslims, police and witnesses said â€” a sign of the sectarian anger that has been arising with greater frequency in Egypt.